1. Field of the Invention
The present invention relates to a peripheral light sensor and a liquid crystal display device using the same, and more particularly to a peripheral light sensor and a liquid crystal display device, which improves output characteristics of the peripheral light sensor and reduces power consumption of the liquid crystal display device.
2. Discussion of Related Art
Recently, various flat panel display devices having reduced weight and volume as compared to cathode ray tubes (CRTS) have been developed. Flat panel displays include liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), and organic light emitting displays (OLEDs).
Since the LCD advantageously has a small size, a light weight, and low power consumption, it has been highlighted as a substitute of the cathode ray tube (CRT). At present, the LCD has been mounted in a monitor or middle to large-sized TV as well as portable devices such as portable phones and portable digital assistants (PDAs). An LCD is a penetrating type of display device, and adjusts an amount of light penetrating a liquid crystal layer by the refraction rate anisotropy of liquid crystal molecules to display desired images.
In the LCD, the back light emitter irradiates light of constant brightness to a pixel portion. However, although a large amount of light is not required for a higher degree of recognition because the brightness of ambient circumstance is dark, light of constant brightness is supplied to the pixel portion. This causes power consumption of the back light emitter to be increased. In practice, the back light emitter consumes greater than 80% of the power required to drive the LCD. Accordingly, to reduce power consumption, a peripheral light is sensed, and when the sensed peripheral light has a brightness less than a predetermined brightness, the amount of light generated by the back light emitter may be reduced.
Moreover, it is desirable to provide a method of improving output characteristics in order to cause a peripheral light sensing signal outputted from the peripheral light sensor to efficiently control a back light driver.